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Dynamically select data frame columns using $ and a character value
...For example, consider the data set mtcars and some variable names stored in a character vector cols . When I try to select a variable from mtcars using a dynamic subset of cols , nether of these work
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round() for float in C++
I need a simple floating point rounding function, thus:
22 Answers
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How do I implement a callback in PHP?
How are callbacks written in PHP?
9 Answers
9
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ERROR 2006 (HY000): MySQL server has gone away
I get this error when I try to source a large SQL file (a big INSERT query).
20 Answers
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What is the difference between a framework and a library?
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Actually these terms can mean a lot of different things depending the context they are used.
For example, on Mac OS X frameworks are just libraries, packed into a bundle. Within the bundle you will find an actual dynamic library (libWhatever.dylib). The difference between a...
Echo equivalent in PowerShell for script testing
I would like to output variables and values out in a PowerShell script by setting up flags and seeing the data matriculate throughout the script.
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How can I list the contents of a directory in Python?
Can’t be hard, but I’m having a mental block.
8 Answers
8
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Look up all descendants of a class in Ruby
I can easily ascend the class hierarchy in Ruby:
15 Answers
15
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How can I force clients to refresh JavaScript files?
We are currently working in a private beta and so are still in the process of making fairly rapid changes, although obviously as usage is starting to ramp up, we will be slowing down this process. That being said, one issue we are running into is that after we push out an update with new JavaScript...
How do I best silence a warning about unused variables?
I have a cross platform application and in a few of my functions not all the values passed to functions are utilised. Hence I get a warning from GCC telling me that there are unused variables.
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